There were three of us under the age of 5 so our backyard looked like a school playground. We didnt have any custom/home-made forts or tree houses, but a bunch of those Fischer Price play gyms and houses. My dad did build me a huge sandbox though. I think it was like 6x6ft. The big oak tree in the backyard had a tire swing on one limb and a climbing rope on the other. The oak tree out front also had a tire swing.

My parents have a photo on their fridge of a Christmas morning when i was like 3 or 4. The living room was stripped of all normal furniture and replaced with some Fischer price play gyms. Pretty crazy.

My dad probably could have built something like this for us because he's really good at that kind of thing, but he never did. We didn't really have a backyard so much as a lot of bush. He did build us a sandpit and a swingset though so it's all good. They took up all the space anyway.

We had an air raid shelter from WW2 that we used as a sort of playhouse. My dad put down a wooden floor for us and we painted the walls. It was pretty neat. He built us a treehouse too, but the tree got knocked down in a hurricane.